Module org.eclipse.jetty.http

Package org.eclipse.jetty.http

Class EtagUtils

java.lang.Object

org.eclipse.jetty.http.EtagUtils

public final class EtagUtils
extends Object

Utility classes for Entity Tag behaviors as outlined in RFC9110 : Section 8.8.3 - Entity Tag

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ETAG_SEPARATOR	The separator within an etag used to indicate a compressed variant.

Method Summary

Modifier and Type	Method	Description
static String	computeWeakEtag(Path path)	Compute the weak etag for the provided Path reference.
static String	computeWeakEtag(Path path, String suffix)	Compute the weak etag for the provided Path reference.
static String	computeWeakEtag(org.eclipse.jetty.util.resource.Resource resource)	Compute the weak etag for the provided Resource reference.
static String	computeWeakEtag(org.eclipse.jetty.util.resource.Resource resource, String etagSuffix)	Compute the weak etag for the provided Resource reference.
static HttpField	createWeakEtagField(org.eclipse.jetty.util.resource.Resource resource)	Create a new HttpField HttpHeader.ETAG field suitable to represent the provided Resource.
static HttpField	createWeakEtagField(org.eclipse.jetty.util.resource.Resource resource, String etagSuffix)	Create a new HttpField HttpHeader.ETAG field suitable to represent the provided Resource.
static boolean	isStrong(String etag)	Test if the given Etag is considered strong (not weak).
static boolean	isWeak(String etag)	Test if the given Etag is considered weak.
static boolean	matches(String etag, String etagWithOptionalSuffix)	Test if etag matches against an etagWithOptionalSuffix.
static String	rewriteWithSuffix(String etag, String newSuffix)	Rewrite etag with a new suffix, satisfying quoting rules, and preserving optional weak flag.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ETAG_SEPARATOR

public static final String ETAG_SEPARATOR

The separator within an etag used to indicate a compressed variant.

Default separator is --

Adding a suffix of gzip to an etag of W/"28c772d6" will result in W/"28c772d6--gzip"

The separator may be changed by the org.eclipse.jetty.http.EtagUtil.ETAG_SEPARATOR System property. If changed, it should be changed to a string that will not be found in a normal etag or at least is very unlikely to be a substring of a normal etag.

Method Details

createWeakEtagField

public static HttpField createWeakEtagField(org.eclipse.jetty.util.resource.Resource resource)

Create a new HttpField HttpHeader.ETAG field suitable to represent the provided Resource.

Parameters:

resource - the resource to represent with an Etag.

Returns:

the field if possible to create etag, or null if not possible.

createWeakEtagField

public static HttpField createWeakEtagField(org.eclipse.jetty.util.resource.Resource resource,
 String etagSuffix)

Create a new HttpField HttpHeader.ETAG field suitable to represent the provided Resource.

Parameters:

resource - the resource to represent with an Etag.

etagSuffix - the suffix for the etag

Returns:

the field if possible to create etag, or null if not possible.

computeWeakEtag

public static String computeWeakEtag(org.eclipse.jetty.util.resource.Resource resource)

Compute the weak etag for the provided Resource reference.

Will use the Resource.getPath() if the resource provides it, otherwise it will use the Resource provided details from Resource.getName(), Resource.lastModified(), and Resource.length() to build the ETag.

Parameters:

resource - the resource to calculate etag from

Returns:

the weak etag

computeWeakEtag

public static String computeWeakEtag(org.eclipse.jetty.util.resource.Resource resource,
 String etagSuffix)

Compute the weak etag for the provided Resource reference.

Will use the Resource.getPath() if the resource provides it, otherwise it will use the Resource provided details from Resource.getName(), Resource.lastModified(), and Resource.length() to build the ETag.

Parameters:

resource - the resource to calculate etag from

etagSuffix - the suffix for the etag

Returns:

the weak etag

computeWeakEtag

public static String computeWeakEtag(Path path)

Compute the weak etag for the provided Path reference.

This supports relative path references as well. Which can be useful to establish a reliable etag if the base changes.

Parameters:

path - the path to calculate from

Returns:

the weak etag

computeWeakEtag

public static String computeWeakEtag(Path path,
 String suffix)

Compute the weak etag for the provided Path reference.

Parameters:

path - the path to calculate from

suffix - the optional suffix for the ETag

Returns:

the weak etag

rewriteWithSuffix

public static String rewriteWithSuffix(String etag,
 String newSuffix)

Rewrite etag with a new suffix, satisfying quoting rules, and preserving optional weak flag.

Parameters:

etag - the original etag

newSuffix - the new suffix to add or change (if a preexisting suffix exists)

Returns:

the new etag,

isWeak

public static boolean isWeak(String etag)

Test if the given Etag is considered weak.

Parameters:

etag - the etag to test

Returns:

true if weak.

isStrong

public static boolean isStrong(String etag)

Test if the given Etag is considered strong (not weak).

Parameters:

etag - the etag to test

Returns:

true if strong (not weak).

matches

public static boolean matches(String etag,
 String etagWithOptionalSuffix)

Test if etag matches against an etagWithOptionalSuffix.

Parameters:

etag - An etag without a compression suffix

etagWithOptionalSuffix - An etag optionally with a compression suffix.

Returns:

True if the tags are equal.

See Also:

• RFC9110: Section 8.8.3.2 - Etag Comparison.